Someone told me about "OpenMystery" a bit ago. It's an emulator that runs the games scripts using the unity engine, so it doesn't have to connect to the JC servers.
The only problem is is that it is PC only, and you can't transfer your save file to it. I'm in volume 2 (year 9) on the base game and in no rush to start over again, so I haven't had the chance to test it yet.